context: copy symlinks as symlinks and improve error messages

src/main.rs

@@ -14,6 +14,17 @@ use log::{error, info};
 
 mod ui;
 
+/// Obtain the current working directory, exiting with a helpful message on failure.
+fn current_dir_or_exit() -> std::path::PathBuf {
+    match std::env::current_dir() {
+        Ok(p) => p,
+        Err(e) => {
+            error!("Could not determine the current working directory: {}", e);
+            std::process::exit(1);
+        }
+    }
+}
+
 fn main() {
     let rt = tokio::runtime::Runtime::new().unwrap();
     let logger =
@@ -137,7 +148,7 @@ fn main() {
             info!("Done.");
         }
         Some(("chlog", sub_matches)) => {
-            let cwd = std::env::current_dir().unwrap();
+            let cwd = current_dir_or_exit();
             let version = sub_matches.get_one::<String>("version").map(|s| s.as_str());
 
             if let Err(e) = generate_entry("debian/changelog", Some(&cwd), version) {
@@ -145,21 +156,38 @@ fn main() {
                 std::process::exit(1);
             }
 
-            let editor = std::env::var("EDITOR").unwrap();
-            let _status = std::process::Command::new(editor)
+            let editor = match std::env::var("EDITOR") {
+                Ok(e) => e,
+                Err(_) => {
+                    error!(
+                        "No editor configured. Set the EDITOR environment variable \
+                         (e.g. `EDITOR=nano` or `export EDITOR=vim`) and retry."
+                    );
+                    std::process::exit(1);
+                }
+            };
+            let _status = std::process::Command::new(&editor)
                 .current_dir(&cwd)
                 .args(["debian/changelog"])
-                .status();
+                .status()
+                .map_err(|e| {
+                    error!(
+                        "Could not launch editor '{}': {}. \
+                         Make sure it is installed and available on PATH.",
+                        editor, e
+                    );
+                    std::process::exit(1);
+                });
         }
         Some(("build", _sub_matches)) => {
-            let cwd = std::env::current_dir().unwrap();
+            let cwd = current_dir_or_exit();
             if let Err(e) = pkh::build::build_source_package(Some(&cwd)) {
                 error!("{}", e);
                 std::process::exit(1);
             }
         }
         Some(("deb", sub_matches)) => {
-            let cwd = std::env::current_dir().unwrap();
+            let cwd = current_dir_or_exit();
             let series = sub_matches.get_one::<String>("series").map(|s| s.as_str());
             let arch = sub_matches.get_one::<String>("arch").map(|s| s.as_str());
             let cross = sub_matches.get_one::<bool>("cross").unwrap_or(&false);
@@ -221,7 +249,13 @@ fn main() {
                         "ssh" => {
                             let endpoint = args
                                 .get_one::<String>("endpoint")
-                                .expect("Endpoint is required for ssh context");
+                                .unwrap_or_else(|| {
+                                    error!(
+                                        "An --endpoint is required to create an ssh context. \
+                                         Expected format: [ssh://][user@]host[:port]"
+                                    );
+                                    std::process::exit(1);
+                                });
 
                             // Parse host, user, port from endpoint
                             // Formats: [ssh://][user@]host[:port]